A general multi-optical axis photoelectric sensor includes a projection unit in which plural projection elements are arrayed in line and a light receiving unit in which plural light receiving elements as many as the projection elements are arrayed in line while the light receiving element is opposite each of the projection elements.
The multi-optical axis photoelectric sensor detects whether each of plural optical axis formed between the projection unit and the light receiving unit is in a light shielding state.
The projection unit sequentially causes the projection element to emit light. In synchronization with emission operation of the projection element, the light receiving unit measures a light reception amount of the light receiving element from the light receiving element corresponding to each projection element. Therefore, the multi-optical axis photoelectric sensor can sequentially detect the light shielding state in each optical axis.
The light receiving unit determines whether an object exists in a detection area formed between the projection unit and the light receiving unit using a detection result of each optical axis, and outputs a signal indicating a determination result. The projection unit and the light receiving unit are connected to each other through a communication line to synchronize the projection unit and the light receiving unit with each other. Alternatively, the projection unit and the light receiving unit are connected to each other by optical communication to synchronize the projection unit and the light receiving unit with each other.
For example, the multi-optical axis photoelectric sensor is installed as a safety device for a worker in a production site. The installed multi-optical axis photoelectric sensor stops operation of a production facility when the light shielding state is detected in one of the optical axes in the detection area. It is necessary to change a setting of the multi-optical axis photoelectric sensor according to the production facility installed in the production site or an environment. In a multi-optical axis photoelectric sensor described in Japanese Unexamined Patent Publication No. 2002-296361, a setting console is connected to the multi-optical axis photoelectric sensor to set definitions of various kinds of detection operation.
However, in the case that the setting console that is of an external device is connected to the multi-optical axis photoelectric sensor, it is necessary to provide a dedicated communication wiring in order to connect the multi-optical axis photoelectric sensor to the external device, or it is necessary to use the communication line between the projection unit and light receiving unit, which may result in an increased number of wirings. Additionally, the number of installed multi-optical axis photoelectric sensors is also increased when the number of installed production facilities is increased in the production site. In the case that many multi-optical axis photoelectric sensors each of which has many wirings are installed, making misconnection of the wiring may be increased with increasing workload of the wiring connection.